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2.3 Earthquake Hazards and Safety

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Vocabulary

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liquefaction: when an earthquake violently shakes, it turns loose, soft soil into mud
aftershock: is an earthquake that happens after a larger earthquake in the same place
tsunamis: large waves formed by underwater earthquakes
base-isolated building: a building made to make the earthquake damage less

Outline

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Introduction

How Earthquakes Causes Damage

• S waves
  • their movements cause severe damage near the epicenter
• Local soil conditions
  • a house built on solid rock
    • shake less
  • a house built on sandy soil
    • shake more
• liquefaction
  • can cause landslides
• aftershocks
  • buildings weakened by a earthquake can collapse during an aftershock
  • could strike anytime after the real earthquake
• tsunamis
  • underwater earthquakes could trigger tsunamis
  • some tsunamis the height of a six-story building
    • wow, that's huge

Making Buildings Safer

• buildings that are more flexible won't crack or break as easily
• stiff buildings will crack and break during an earthquake
• choice of location
  • steep slopes could be dangerous to landslides
  • filled land will shake a lot
  • avoid building structures near earthquake faults
• constructing methods
  • brick buildings and wood-frame buildings will probably collapse if walls have not been sturdied
  • base-isolated buildings are safer

Protecting Yourself During an Earthquake

• drop, cover, hold
  • hide beneath a desk or table to protect yourself from falling objects
• if outside, go to a opened space area
  • no telephone poles or things that can fall on you